Mill to produce spiral-welded double layer pipes

ABSTRACT

A mill to produce spiral-welded double layer pipes, wherein the strip feeding rolls are combined into two groups each of which feeds one of the strips, and the axes of the rolls rotation are horizontally disposed, these rolls being mounted at an angle, the value of which depends on the pipe diameter and the width of the strips.

United States Patent Tselikov et al.

[54] MILL TO PRODUCE SPIRAL-WELDED DOUBLE LAYER PIPES [72] inventors: Alexandr lvanovich Tsellkov, ulitsa Chernyakhovskogo, 4, kv. 127; Nikolai Ale eevich Grum-Grzhimailo, Sharikopodshipnikovskaya ulitsa, 2-'a, kv. 7; Vadim Anatolievich Verderevsky, Volgogradsky prospekt, 171, kv. 35, all of Moscow; Alexandr Borisovich Vernik, prospekt Lenina, '30, i3, kv. S4, Elektrostal Moskovskoi Oblasti; Boris Pavlovich Skorupsky, ulitsa Pushkina, l9/l6, kv. 68, Elektrostal Moskovskoi Oblasti; Igor II- larionovich Kazakevich, prospekt Lenina, 28, kv. 44, Elektrostal Moskovskoi Oblasti; Ivan Vasilievich Kuznetsov, ulitsa Sovetskaya, 42, kv. l4, Novomoskovsk, all ofU,S.S.R.

[22] Filed: Dec. 18, I969 21 -Appl. 1516.; 86,268,

[52] U8. Cl ..228/15, 29/477.7, 219/62,

' 228/17 [51 Int. Cl ..B23k'l/20 [58] Field of Search ..219/62; 228/5, 15, 7; 93/77,

93/80, 81 R, 81 MT; 29/33 1), 4741, 477.3, 477.7, 479;]13/l16UT [151 3,661,314 14 1 May 9,1972

References Cited UNITED STATES PATENTS 379,937 3/1888 Coas.., ..29/477.3 2,549,032 4/1951 Taylor. ..113/116 2,786,435 3/1957 Ellzey ..113/116 2,845,!09 7/l958 Schneider... .....29/477.3 x 2,991,740 7/l 96l 12610161111 ..-22 /15 I 3,2l0,980 10/1965 Sengel ....22s/1sx 3,217,402 11/1965 Eckhardt. ....228/15x 3,385,179 5/1968 1166,11 ..93/81 x PrimaryE\'an1iner-John F. Campbell Assistant Examiner-Robert J. Craig Attorney-Holman andStern 57, I ABSTRACT I A mill to produce spiralwelded double layer pipes, wherein the strip feeding rolls are combined into two groups each of which feeds one ofthe strips, and the axes of the rolls rotation are horizontally'disposed, these'rolls being mounted at an angle, the value of which depends on the pipe diameter and the width of the strips. 1

3 Claims, 5 Drawing Figures The present invention relates to pipe mills, and more specifically to welding mills wherein double ply pipes are manufactured by spiral welding.

The proposed invention can be most successfully used in the production of double layer pipes with a diameter of over 1,020 mm. for high-pressure pipelines made of thin strips, but it can equally be employed to produce pipes from strips of different metals, or metals with different mechanical properties.

Known presently in the art are mills for the production of spiral-welded double. layer pipes, comprising successively located arrangements to prepare the strips for welding, and rolls to feed the strips into the forming and welding machine wherefrom the welded double layer pipe comes out, the rolls feeding together both the strips imposed one on the other.

As in the production of double layer pipes the outer strip should embrace the inner one, the rate of feed of the outer strip must exceed that of the inner one. This is achieved in the previous mills only on account of positive slipping of the strips one relative to another, or heating of the strip forming the outside layer of the pipe. Obviously, this operation is difficult to realize.

The object of the invention is to provide a mill for producing double layer pipes, that provides for separate strip feeding into the forming and welding machine, with individual adjustment of the angle of entrance of each strip.

This object is achieved in that in a mill for producing double layer pipes, comprising successively located arrangements to prepare the strips for welding, and rolls to feed the strips into the forming and welding machine, wherefrom a welded double layer pipe comes out, the rolls are, according to the invention, combined into at least two groups, each of which feeds only one of the strips, the axes of the rolls rotation in each group being horizontally disposed, and the rolls of one group being mounted at an angle B to the rolls of the other group, the value of this angle being determined in degrees by formula ALA B-arc cos 77D where B, is the width of the strip forming the inner layer of the pipe, in millimeters; B is the width of the strip forming the outer pipe layer, in millimeters; D, is the diameter of the pipe inner layer, in millimeters; D is the diameter of the pipe outer layer, in millimeters. Such a design permits feeding the strips separately and at different angles into the forming and welding machine.

It is advisable to mount one group of rolls so that it can be rotated with respect to the other group of rolls about an axis perpendicular to the longitudinal axis of the pipe, in order to correct angle ,8. This enables separate adjustment of the angle of entrance of each strip into the fon'ning and welding machine.

The rolls rotatable about the vertical axis can be mounted on a stand rigidly secured to a frame, which is rotated by an electric drive about a fixed vertical axle perpendicularly to the longitudinal axis, of the pipe, rolls are pressed to one another.

To give a better understanding of the invention, considered below is a particular embodiment thereof with reference to the appended drawings, wherein:

FIG. 1 is a general view of the mill according to the invention, side view;

FIG. 2 shows the lay-out of the strips for the production of a double layer pipe;

FIG. 3 shows the feeding rolls, enlarged side view;

FIG. 4 shows the same lay-out, as in FIG. 2, the strips being shifted relative to each other;

FIG. 5 shows the mill according to the invention, top view.

The mill for the production of double layer pipes comprises successively located arrangements 1 and 2 (FIG. 1) for preparing strips 3 and 4 for welding, and rolls 5, 6, 7, and 8 combined into two groups respectively feeding strips 3 and 4 into a forming and welding machine 9, wherefrom a double layer pipe comes out.

The longitudinal axes of rolls 5-8 are all disposed in the horizontal plane, rolls 7 and 8, which form one group, being mounted at an angle B (FIG. 2) to rolls 5 and 6 forming another group. This angle depends on the width and thickness of the strips, as well as on the diameter of the pipe. The value of this angle is determined in degrees by formula B= arc COS 12 about a vertical axis 13 by means of an electric drive means 14. Axle 13 is immovable, and is perpendicular to the longitudinal axis of pipe 15. Rolls 7 and 8 are pressed to one another by shackle 16, one end of which is articulated to stand 10, and the other end of which is through pin 17 connected with piston rod 18 of a hydraulic cylinder 19 whose body is hinged to stand 10.

Disposed behind rolls 7 and 8 in the direction of movement of strip 3 (conventionally shown by arrow A) are stationary guide rollers 20 mounted on a common base 21, which is fixed on stand 10.

The above formula characterizing the relationship between angle [3, the width and thickness of the strips, and the pipe diameter, is derived under the conditions that angle B equals the the difference between angles a and a, (FIG. 2), where a, is the angle between the edge of strip 4 and the longitudinal axis of pipe 15 and, a is the angle between the edge of strip 3 and the longitudinal axis of pipe 15.

Adjustment of the welding gap between the edge of strip 3 and the first coil of the pipe in the outside layer thereof is done by correcting angle 01,. This is realized by turning frame 11 (FIG. 3) together with rolls 7 and 8 about the vertical axle l3.

Feeding of strips 3 and 4 at different angles is necessary to secure equal axial components of the rates of feed of the strips into the forming and welding machine, which is one of the vital conditions in forming double layer pipes.

The forming and welding machine 9 is fixed on base 22, which is through rollers 23 mounted on frame 24. This frame is rotatable about the vertical axle 13 by means of an electric drive means 25.

Base 22 can turn together with machine 9 about axle 13, using an electric drive means 26, thus setting machine 9 in the required position which is determined according to the diameter of the pipe to be made, and the width of strips 3 and 4.

The position of pipe 15 emerging from machine 9, with respect to frame 24 is fixed by means of rests 27 (FIG. 5) mounted on this frame.

Adjustment of the welding gap between the edge of strip 4 and the first coil of the pipe in the inside layer thereof is effected by varying angle a, (FIG. 2). This is done by turning frame 24 together with pipe 15 (FIG. 3) about axle 13 or by simultaneously rotating frame 24 and base 22 together with the forming and welding machine 9 about axle 13.

Rolls 5 and 6 are mounted in a fixed stand 28, and are pressed to each other by shackle 29. One end of this shackle is hinged to stand 28, while the other end is through pin 30 connected with the piston rod 31 of a hydraulic cylinder 32. The body of this hydraulic cylinder is hinged on stand 28.

Located after rolls 5 and 6 in the way of movement of strip 4 (conventionally shown with arrow B) are guide rollers 33 mounted on a common base 34.

Strips 3 and 4 fed into the forming and welding machine with a displacement relative to one another, to a value a, as shown in FIGS. 4 and 5. This shift is necessary to secure the possibility of one-side welding, of both the inner and the outer pipe layers, on the adjacent layer without burning through the layer being welded.

Each of arrangements 1 or 2 (FIG. 1) comprises an unwinder 35 of the coils of strips 3 and 4, a straightening machine 36, shears 37 for transverse cutting of the strips, a butt-welding machine 38 with a burring attachment, circular shears 39 for gauging the strips in width, and feeding rollers 40.

The mill is mounted on footing 41, which has pits 42 and 43 to dispose the loops of strips 3 and 4.

The loop of strip 3 formed in pit 42 is necessary to have a strip reserve ensuring continuous operation of the mill when the ends of the strips are jointed in arrangement 1.

The loop of strip 4 formed in pit 43 is necessary to provide a strip reserve ensuring continuous operation of the mill when jointing the ends of the strips in arrangement 2, and the second loop of strip 3 formed in pit 43 so as to have a permanent length, secures the possibility of varying the angle of entrance of this strip into the forming and welding machine on account of its distortion in this pit.

During the mill operation the reeled strips undergoing in arrangements l and 2 the successive operations of unwinding, straightening, ends shearing, butt-welding, and width-gauging, arrive at pits 42 and 43 (FIG. 1), where they form loops providing for the continuity of the mill operation while the ends of the strips are jointed in the preparative arrangements 1 and 2.

The strips 3 and 4 are pulled out from the pits by rolls 5-8, which feed them into the forming and welding machine at different angles to the longitudinal axis of pipe 15. The feed of strips under different angles provides for equal axial components of the rates of feed of the strips as they are bent to different diameters at the moment of forming the double layer pipe.

1f the edges of strips 3 and 4 are curved, it is necessary to adjust the welding gap in the inner and outer pipe layers. Adjustment of the gap in the inside layer is done by turing frame 24 (FIG. 3) together with pipe about axle 13, or by simultaneous rotation of this frame and base 22 with the forming and welding machine 9. The gap in the outside layer is adjusted by turning frame ll together with rolls 7 and 8.

In the forming and welding machine 9 (FIG. 1) strips 3 and 4 are rolled up along a helix (as is shown in FIG. 5) into a cylindrical pipe blank, and the helical seams of the inside and outside pipe layers are simultaneously welded. The inside layer is welded by apparatus 44 (FIG. 1) in the place of convergence of the edge of strip 4 with the first coil of the inside layer, while the outside layer is welded by apparatus 45 half a turn after the place of welding of the inside layer. The pipe emerging from machine 9 can be cut to gauge length while the machine is running, to be then carried away for subsequent working.

What we claim is:

l. A mill to produce spiral-welded double layer pipes, comprising: successively located arrangements to prepare at least two strips for welding; rolls combined into at least two groups of rolls each of which groups feeds one of the strips; a forming and welding machine, whereinto the strips are fed by said groups of rolls, and wherefrom emerges the welded double layer pipe; the rotational axes of the rolls in each of said groups being horizontally disposed, the rolls of one group being mounted at an angle [3 to the rolls of the other group, the value of this angle being determined in degrees by formula where B, is the width of the strip forming the inner layer of the pipe, in millimeters; B is the width of the strip forming the outer layer of the pipe, in millimeters; D is the diameter of the pipe inner layer, in millimeters; D is the diameter of the pipe outer layer, in millimeters.

2. A mill, as in claim 1, wherein one group of rolls is mounted so as to be capable of being turned with respect to the other group of rolls about a vertical axis perpendicular to the longitudinal axis of the pipe, in order to vary angle B.

3. A mill, as in claim 2, wherein the rolls turnable about the vertical axis are mounted on a stand rigidly secured to a frame, which 15 rotated by an electric drive means about a fixed vertical axle perpendicular to the longitudinal axis of the pipe, while the rolls are pressed to one another. 

1. A mill to produce spiral-welded double layer pipes, comprising: successively located arrangements to prepare at least two strips for welding; rolls combined into at least two groups of rolls each of which groups feeds one of the strips; a forming and welding machine, whereinto the strips are fed by said groups of rolls, and wherefrom emerges the welded double layer pipe; the rotational axes of the rolls in each of said groups being horizontally disposed, the rolls of one group being mounted at an angle Beta to the rolls of the other group, the value of this angle being determined in degrees by formula where B1 is the width of the strip forming the inner layer of the pipe, in millimeters; B2 is the width of the strip forming the outer layer of the pipe, in millimeters; D1 is the diameter of the pipe inner layer, in millimeters; D2 is the diameter of the pipe outer layer, in millimeters.
 2. A mill, as in claim 1, wherein one group of rolls is mounted so as to be capable of being turned with respect to the other group of rolls about a vertical axis perpendicular to the longitudinal axis of the pipe, in order to vary angle Beta .
 3. A mill, as in claim 2, wherein the rolls turnable about the vertical axis are mounted on a stand rigidly secured to a frame, which is rotated by an electric drive means about a fixed vertical axle perpendicular to the longitudinal axis of the pipe, while the rolls are pressed to one another. 